to create webcam Visual on ASP.NET Web page.

Question

hi,

I want to add my webcam visual to ASP.NET web page, my webcam is detected by "FilterInfoCollectionvideoDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice)" Method. But When the line "VideoCaptureDevice videoSource = new VideoCaptureDevice(videoDevices[DropDownList1.SelectedIndex].MonikerString)" execute is return error- "Object reference not set to an instance of an object." how can I over come this problem..

 Please help me to solve this problem.

 

 

this is my full program:

 

 

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using AForge.Video;

using AForge.Video.DirectShow;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Drawing.Imaging;

public partial class index : System.Web.UI.Page

{

private bool DeviceExist = false;

private FilterInfoCollection videoDevices;

private VideoCaptureDevice videoSource = null;

protected void Page_Load(object sender, EventArgs e)

{

}

private void getCamList()

{

try

{

videoDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice);

DropDownList1.Items.Clear();

if (videoDevices.Count == 0)

throw new ApplicationException();

DeviceExist = true;

foreach (FilterInfo device in videoDevices)

{

DropDownList1.Items.Add(device.Name);

}

DropDownList1.SelectedIndex = 0; //make dafault to first cam

}

catch (ApplicationException)

{

DeviceExist = false;

DropDownList1.Items.Add("No capture device on your system");

}

}

protected void Button1_Click(object sender, EventArgs e)

{

getCamList();

}

protected void Button2_Click(object sender, EventArgs e)

{

if (start.Text == "&Start")

{

if (DeviceExist)

{

videoSource = new VideoCaptureDevice(videoDevices[DropDownList1.SelectedIndex].MonikerString);

videoSource.NewFrame += new NewFrameEventHandler(video_NewFrame);

CloseVideoSource();

videoSource.DesiredFrameSize = new Size(160, 120);

//videoSource.DesiredFrameRate = 10;

videoSource.Start();

Label2.Text = "Device running...";

start.Text = "&Stop";

Timer1.Enabled = true;

}

else

{

Label2.Text = "Error: No Device selected.";

}

}

else

{

if (videoSource.IsRunning)

{

Timer1.Enabled = false;

CloseVideoSource();

Label2.Text = "Device stopped.";

start.Text = "&Start";

}

}

}

private void video_NewFrame(object sender, NewFrameEventArgs eventArgs)

{

Bitmap img = (Bitmap)eventArgs.Frame.Clone();

//do processing here

// pictureBox1.Image = img;

}

private void CloseVideoSource()

{

if (!(videoSource == null))

if (videoSource.IsRunning)

{

videoSource.SignalToStop();

videoSource = null;

}

}

protected void Timer1_Tick(object sender, EventArgs e)

{

Label2.Text = "Device running... " + videoSource.FramesReceived.ToString() + " FPS";

}

}